This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A323272 #12 Jan 12 2019 02:31:40 %S A323272 65,85,185,265,365,481,485,493,533,565,629,685,697,785,865,949,965, %T A323272 985,1037,1073,1157,1165,1189,1241,1261,1285,1385,1417,1465,1565,1585, %U A323272 1649,1685,1765,1769,1781,1853,1865,1921,1937,1985,2117,2165,2173 %N A323272 Numbers of the form p_1*p_2*p_3*...*p_r where r is 2 or an odd number > 2, and the p_i are distinct primes congruent to 1 mod 4 such that Legendre(p_i/p_j) = -1 for all i != j. %C A323272 If k is a term, the Pell equation x^2 - k*y^2 = -1 has a solution [Dirichlet, Newman (1977)]. This is only a sufficient condition, there are many other solutions, see A031396. %H A323272 Chai Wah Wu, <a href="/A323272/b323272.txt">Table of n, a(n) for n = 1..10000</a> %H A323272 Morris Newman, <a href="https://www.jstor.org/stable/2319968">A note on an equation related to the Pell equation</a>, The American Mathematical Monthly 84.5 (1977): 365-366. %Y A323272 Cf. A002144, A031396. Includes the union of A322781 and A323271. %K A323272 nonn %O A323272 1,1 %A A323272 _N. J. A. Sloane_, Jan 11 2019